EZdrummer comes with the basic POP/ROCK kit and the Cocktail EZX.
Sure, users have posted Metal Demos with POP/ROCK but then they have tweaked the sound in their hosts (e.g. Logic).
Toontrack solo is a free host app for Toontrack users and it loads Toontrack plugins only.

So, E-drummers only using EZdrummer for live playing get along well with EZdrummer and Toontrack solo.
E-drummers wanting to record their performances and to have full control and tweakability buy Superior 2.

Best Regards,
John